2 % (c) The University of Glasgow 2006
3 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
9 -- GHC uses several kinds of name internally:
11 -- * 'OccName.OccName' represents names as strings with just a little more information:
12 -- the \"namespace\" that the name came from, e.g. the namespace of value, type constructors or
15 -- * 'RdrName.RdrName': see "RdrName#name_types"
17 -- * 'Name.Name': see "Name#name_types"
19 -- * 'Id.Id': see "Id#name_types"
21 -- * 'Var.Var': see "Var#name_types"
23 -- * The 'NameSpace' type
24 NameSpace, -- Abstract
27 -- $real_vs_source_data_constructors
28 tcName, clsName, tcClsName, dataName, varName,
32 pprNameSpace, pprNonVarNameSpace, pprNameSpaceBrief,
34 -- * The 'OccName' type
35 OccName, -- Abstract, instance of Outputable
39 mkOccName, mkOccNameFS,
41 mkDataOcc, mkDataOccFS,
42 mkTyVarOcc, mkTyVarOccFS,
49 -- ** Derived 'OccName's
51 mkDataConWrapperOcc, mkWorkerOcc, mkDefaultMethodOcc,
52 mkDerivedTyConOcc, mkNewTyCoOcc, mkClassOpAuxOcc,
53 mkCon2TagOcc, mkTag2ConOcc, mkMaxTagOcc,
54 mkClassTyConOcc, mkClassDataConOcc, mkDictOcc, mkIPOcc,
55 mkSpecOcc, mkForeignExportOcc, mkGenOcc1, mkGenOcc2,
56 mkDataTOcc, mkDataCOcc, mkDataConWorkerOcc,
57 mkSuperDictSelOcc, mkLocalOcc, mkMethodOcc, mkInstTyTcOcc,
58 mkInstTyCoOcc, mkEqPredCoOcc,
59 mkVectOcc, mkVectTyConOcc, mkVectDataConOcc, mkVectIsoOcc,
60 mkPDataTyConOcc, mkPDataDataConOcc,
65 occNameFS, occNameString, occNameSpace,
67 isVarOcc, isTvOcc, isTcOcc, isDataOcc, isDataSymOcc, isSymOcc, isValOcc,
68 parenSymOcc, startsWithUnderscore,
70 isTcClsNameSpace, isTvNameSpace, isDataConNameSpace, isVarNameSpace, isValNameSpace,
74 -- * The 'OccEnv' type
75 OccEnv, emptyOccEnv, unitOccEnv, extendOccEnv, mapOccEnv,
76 lookupOccEnv, mkOccEnv, mkOccEnv_C, extendOccEnvList, elemOccEnv,
77 occEnvElts, foldOccEnv, plusOccEnv, plusOccEnv_C, extendOccEnv_C,
78 extendOccEnv_Acc, filterOccEnv, delListFromOccEnv, delFromOccEnv,
80 -- * The 'OccSet' type
81 OccSet, emptyOccSet, unitOccSet, mkOccSet, extendOccSet,
83 unionOccSets, unionManyOccSets, minusOccSet, elemOccSet, occSetElts,
84 foldOccSet, isEmptyOccSet, intersectOccSet, intersectsOccSet,
87 TidyOccEnv, emptyTidyOccEnv, tidyOccName, initTidyOccEnv,
89 -- * Lexical characteristics of Haskell names
90 isLexCon, isLexVar, isLexId, isLexSym,
91 isLexConId, isLexConSym, isLexVarId, isLexVarSym,
92 startsVarSym, startsVarId, startsConSym, startsConId
107 -- Unicode TODO: put isSymbol in libcompat
108 #if !defined(__GLASGOW_HASKELL__) || __GLASGOW_HASKELL__ > 604
110 isSymbol :: a -> Bool
111 isSymbol = const False
116 %************************************************************************
118 \subsection{Name space}
120 %************************************************************************
123 data NameSpace = VarName -- Variables, including "real" data constructors
124 | DataName -- "Source" data constructors
125 | TvName -- Type variables
126 | TcClsName -- Type constructors and classes; Haskell has them
127 -- in the same name space for now.
129 {-! derive: Binary !-}
131 -- Note [Data Constructors]
132 -- see also: Note [Data Constructor Naming] in DataCon.lhs
134 -- $real_vs_source_data_constructors
135 -- There are two forms of data constructor:
137 -- [Source data constructors] The data constructors mentioned in Haskell source code
139 -- [Real data constructors] The data constructors of the representation type, which may not be the same as the source type
143 -- > data T = T !(Int, Int)
145 -- The source datacon has type @(Int, Int) -> T@
146 -- The real datacon has type @Int -> Int -> T@
148 -- GHC chooses a representation based on the strictness etc.
150 tcName, clsName, tcClsName :: NameSpace
151 dataName, srcDataName :: NameSpace
152 tvName, varName :: NameSpace
154 -- Though type constructors and classes are in the same name space now,
155 -- the NameSpace type is abstract, so we can easily separate them later
156 tcName = TcClsName -- Type constructors
157 clsName = TcClsName -- Classes
158 tcClsName = TcClsName -- Not sure which!
161 srcDataName = DataName -- Haskell-source data constructors should be
162 -- in the Data name space
167 isDataConNameSpace :: NameSpace -> Bool
168 isDataConNameSpace DataName = True
169 isDataConNameSpace _ = False
171 isTcClsNameSpace :: NameSpace -> Bool
172 isTcClsNameSpace TcClsName = True
173 isTcClsNameSpace _ = False
175 isTvNameSpace :: NameSpace -> Bool
176 isTvNameSpace TvName = True
177 isTvNameSpace _ = False
179 isVarNameSpace :: NameSpace -> Bool -- Variables or type variables, but not constructors
180 isVarNameSpace TvName = True
181 isVarNameSpace VarName = True
182 isVarNameSpace _ = False
184 isValNameSpace :: NameSpace -> Bool
185 isValNameSpace DataName = True
186 isValNameSpace VarName = True
187 isValNameSpace _ = False
189 pprNameSpace :: NameSpace -> SDoc
190 pprNameSpace DataName = ptext (sLit "data constructor")
191 pprNameSpace VarName = ptext (sLit "variable")
192 pprNameSpace TvName = ptext (sLit "type variable")
193 pprNameSpace TcClsName = ptext (sLit "type constructor or class")
195 pprNonVarNameSpace :: NameSpace -> SDoc
196 pprNonVarNameSpace VarName = empty
197 pprNonVarNameSpace ns = pprNameSpace ns
199 pprNameSpaceBrief :: NameSpace -> SDoc
200 pprNameSpaceBrief DataName = char 'd'
201 pprNameSpaceBrief VarName = char 'v'
202 pprNameSpaceBrief TvName = ptext (sLit "tv")
203 pprNameSpaceBrief TcClsName = ptext (sLit "tc")
207 %************************************************************************
209 \subsection[Name-pieces-datatypes]{The @OccName@ datatypes}
211 %************************************************************************
214 data OccName = OccName
215 { occNameSpace :: !NameSpace
216 , occNameFS :: !FastString
222 instance Eq OccName where
223 (OccName sp1 s1) == (OccName sp2 s2) = s1 == s2 && sp1 == sp2
225 instance Ord OccName where
226 -- Compares lexicographically, *not* by Unique of the string
227 compare (OccName sp1 s1) (OccName sp2 s2)
228 = (s1 `compare` s2) `thenCmp` (sp1 `compare` sp2)
232 %************************************************************************
234 \subsection{Printing}
236 %************************************************************************
239 instance Outputable OccName where
242 pprOccName :: OccName -> SDoc
243 pprOccName (OccName sp occ)
244 = getPprStyle $ \ sty ->
246 then ftext (zEncodeFS occ)
247 else ftext occ <> if debugStyle sty
248 then braces (pprNameSpaceBrief sp)
253 %************************************************************************
255 \subsection{Construction}
257 %************************************************************************
260 mkOccName :: NameSpace -> String -> OccName
261 mkOccName occ_sp str = OccName occ_sp (mkFastString str)
263 mkOccNameFS :: NameSpace -> FastString -> OccName
264 mkOccNameFS occ_sp fs = OccName occ_sp fs
266 mkVarOcc :: String -> OccName
267 mkVarOcc s = mkOccName varName s
269 mkVarOccFS :: FastString -> OccName
270 mkVarOccFS fs = mkOccNameFS varName fs
272 mkDataOcc :: String -> OccName
273 mkDataOcc = mkOccName dataName
275 mkDataOccFS :: FastString -> OccName
276 mkDataOccFS = mkOccNameFS dataName
278 mkTyVarOcc :: String -> OccName
279 mkTyVarOcc = mkOccName tvName
281 mkTyVarOccFS :: FastString -> OccName
282 mkTyVarOccFS fs = mkOccNameFS tvName fs
284 mkTcOcc :: String -> OccName
285 mkTcOcc = mkOccName tcName
287 mkTcOccFS :: FastString -> OccName
288 mkTcOccFS = mkOccNameFS tcName
290 mkClsOcc :: String -> OccName
291 mkClsOcc = mkOccName clsName
293 mkClsOccFS :: FastString -> OccName
294 mkClsOccFS = mkOccNameFS clsName
298 %************************************************************************
302 %************************************************************************
304 OccEnvs are used mainly for the envts in ModIfaces.
306 Note [The Unique of an OccName]
307 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
308 They are efficient, because FastStrings have unique Int# keys. We assume
309 this key is less than 2^24, and indeed FastStrings are allocated keys
310 sequentially starting at 0.
312 So we can make a Unique using
313 mkUnique ns key :: Unique
314 where 'ns' is a Char reprsenting the name space. This in turn makes it
315 easy to build an OccEnv.
318 instance Uniquable OccName where
319 -- See Note [The Unique of an OccName]
320 getUnique (OccName VarName fs) = mkVarOccUnique fs
321 getUnique (OccName DataName fs) = mkDataOccUnique fs
322 getUnique (OccName TvName fs) = mkTvOccUnique fs
323 getUnique (OccName TcClsName fs) = mkTcOccUnique fs
325 newtype OccEnv a = A (UniqFM a)
327 emptyOccEnv :: OccEnv a
328 unitOccEnv :: OccName -> a -> OccEnv a
329 extendOccEnv :: OccEnv a -> OccName -> a -> OccEnv a
330 extendOccEnvList :: OccEnv a -> [(OccName, a)] -> OccEnv a
331 lookupOccEnv :: OccEnv a -> OccName -> Maybe a
332 mkOccEnv :: [(OccName,a)] -> OccEnv a
333 mkOccEnv_C :: (a -> a -> a) -> [(OccName,a)] -> OccEnv a
334 elemOccEnv :: OccName -> OccEnv a -> Bool
335 foldOccEnv :: (a -> b -> b) -> b -> OccEnv a -> b
336 occEnvElts :: OccEnv a -> [a]
337 extendOccEnv_C :: (a->a->a) -> OccEnv a -> OccName -> a -> OccEnv a
338 extendOccEnv_Acc :: (a->b->b) -> (a->b) -> OccEnv b -> OccName -> a -> OccEnv b
339 plusOccEnv :: OccEnv a -> OccEnv a -> OccEnv a
340 plusOccEnv_C :: (a->a->a) -> OccEnv a -> OccEnv a -> OccEnv a
341 mapOccEnv :: (a->b) -> OccEnv a -> OccEnv b
342 delFromOccEnv :: OccEnv a -> OccName -> OccEnv a
343 delListFromOccEnv :: OccEnv a -> [OccName] -> OccEnv a
344 filterOccEnv :: (elt -> Bool) -> OccEnv elt -> OccEnv elt
346 emptyOccEnv = A emptyUFM
347 unitOccEnv x y = A $ unitUFM x y
348 extendOccEnv (A x) y z = A $ addToUFM x y z
349 extendOccEnvList (A x) l = A $ addListToUFM x l
350 lookupOccEnv (A x) y = lookupUFM x y
351 mkOccEnv l = A $ listToUFM l
352 elemOccEnv x (A y) = elemUFM x y
353 foldOccEnv a b (A c) = foldUFM a b c
354 occEnvElts (A x) = eltsUFM x
355 plusOccEnv (A x) (A y) = A $ plusUFM x y
356 plusOccEnv_C f (A x) (A y) = A $ plusUFM_C f x y
357 extendOccEnv_C f (A x) y z = A $ addToUFM_C f x y z
358 extendOccEnv_Acc f g (A x) y z = A $ addToUFM_Acc f g x y z
359 mapOccEnv f (A x) = A $ mapUFM f x
360 mkOccEnv_C comb l = A $ addListToUFM_C comb emptyUFM l
361 delFromOccEnv (A x) y = A $ delFromUFM x y
362 delListFromOccEnv (A x) y = A $ delListFromUFM x y
363 filterOccEnv x (A y) = A $ filterUFM x y
365 instance Outputable a => Outputable (OccEnv a) where
368 type OccSet = UniqSet OccName
370 emptyOccSet :: OccSet
371 unitOccSet :: OccName -> OccSet
372 mkOccSet :: [OccName] -> OccSet
373 extendOccSet :: OccSet -> OccName -> OccSet
374 extendOccSetList :: OccSet -> [OccName] -> OccSet
375 unionOccSets :: OccSet -> OccSet -> OccSet
376 unionManyOccSets :: [OccSet] -> OccSet
377 minusOccSet :: OccSet -> OccSet -> OccSet
378 elemOccSet :: OccName -> OccSet -> Bool
379 occSetElts :: OccSet -> [OccName]
380 foldOccSet :: (OccName -> b -> b) -> b -> OccSet -> b
381 isEmptyOccSet :: OccSet -> Bool
382 intersectOccSet :: OccSet -> OccSet -> OccSet
383 intersectsOccSet :: OccSet -> OccSet -> Bool
385 emptyOccSet = emptyUniqSet
386 unitOccSet = unitUniqSet
388 extendOccSet = addOneToUniqSet
389 extendOccSetList = addListToUniqSet
390 unionOccSets = unionUniqSets
391 unionManyOccSets = unionManyUniqSets
392 minusOccSet = minusUniqSet
393 elemOccSet = elementOfUniqSet
394 occSetElts = uniqSetToList
395 foldOccSet = foldUniqSet
396 isEmptyOccSet = isEmptyUniqSet
397 intersectOccSet = intersectUniqSets
398 intersectsOccSet s1 s2 = not (isEmptyOccSet (s1 `intersectOccSet` s2))
402 %************************************************************************
404 \subsection{Predicates and taking them apart}
406 %************************************************************************
409 occNameString :: OccName -> String
410 occNameString (OccName _ s) = unpackFS s
412 setOccNameSpace :: NameSpace -> OccName -> OccName
413 setOccNameSpace sp (OccName _ occ) = OccName sp occ
415 isVarOcc, isTvOcc, isTcOcc, isDataOcc :: OccName -> Bool
417 isVarOcc (OccName VarName _) = True
420 isTvOcc (OccName TvName _) = True
423 isTcOcc (OccName TcClsName _) = True
426 -- | /Value/ 'OccNames's are those that are either in
427 -- the variable or data constructor namespaces
428 isValOcc :: OccName -> Bool
429 isValOcc (OccName VarName _) = True
430 isValOcc (OccName DataName _) = True
433 isDataOcc (OccName DataName _) = True
434 isDataOcc (OccName VarName s)
435 | isLexCon s = pprPanic "isDataOcc: check me" (ppr s)
436 -- Jan06: I don't think this should happen
439 -- | Test if the 'OccName' is a data constructor that starts with
440 -- a symbol (e.g. @:@, or @[]@)
441 isDataSymOcc :: OccName -> Bool
442 isDataSymOcc (OccName DataName s) = isLexConSym s
443 isDataSymOcc (OccName VarName s)
444 | isLexConSym s = pprPanic "isDataSymOcc: check me" (ppr s)
445 -- Jan06: I don't think this should happen
446 isDataSymOcc _ = False
447 -- Pretty inefficient!
449 -- | Test if the 'OccName' is that for any operator (whether
450 -- it is a data constructor or variable or whatever)
451 isSymOcc :: OccName -> Bool
452 isSymOcc (OccName DataName s) = isLexConSym s
453 isSymOcc (OccName TcClsName s) = isLexConSym s
454 isSymOcc (OccName VarName s) = isLexSym s
455 isSymOcc (OccName TvName s) = isLexSym s
456 -- Pretty inefficient!
458 parenSymOcc :: OccName -> SDoc -> SDoc
459 -- ^ Wrap parens around an operator
460 parenSymOcc occ doc | isSymOcc occ = parens doc
466 startsWithUnderscore :: OccName -> Bool
467 -- ^ Haskell 98 encourages compilers to suppress warnings about unsed
468 -- names in a pattern if they start with @_@: this implements that test
469 startsWithUnderscore occ = case occNameString occ of
475 %************************************************************************
477 \subsection{Making system names}
479 %************************************************************************
481 Here's our convention for splitting up the interface file name space:
483 d... dictionary identifiers
484 (local variables, so no name-clash worries)
486 All of these other OccNames contain a mixture of alphabetic
487 and symbolic characters, and hence cannot possibly clash with
488 a user-written type or function name
490 $f... Dict-fun identifiers (from inst decls)
491 $dmop Default method for 'op'
492 $pnC n'th superclass selector for class C
493 $wf Worker for functtoin 'f'
494 $sf.. Specialised version of f
495 T:C Tycon for dictionary for class C
496 D:C Data constructor for dictionary for class C
497 NTCo:T Coercion connecting newtype T with its representation type
498 TFCo:R Coercion connecting a data family to its respresentation type R
500 In encoded form these appear as Zdfxxx etc
502 :... keywords (export:, letrec: etc.)
503 --- I THINK THIS IS WRONG!
505 This knowledge is encoded in the following functions.
507 @mk_deriv@ generates an @OccName@ from the prefix and a string.
508 NB: The string must already be encoded!
511 mk_deriv :: NameSpace
512 -> String -- Distinguishes one sort of derived name from another
516 mk_deriv occ_sp sys_prefix str = mkOccName occ_sp (sys_prefix ++ str)
518 isDerivedOccName :: OccName -> Bool
519 isDerivedOccName occ =
520 case occNameString occ of
521 '$':c:_ | isAlphaNum c -> True
522 ':':c:_ | isAlphaNum c -> True
527 mkDataConWrapperOcc, mkWorkerOcc, mkDefaultMethodOcc, mkDerivedTyConOcc,
528 mkClassTyConOcc, mkClassDataConOcc, mkDictOcc, mkIPOcc,
529 mkSpecOcc, mkForeignExportOcc, mkGenOcc1, mkGenOcc2,
530 mkDataTOcc, mkDataCOcc, mkDataConWorkerOcc, mkNewTyCoOcc,
531 mkInstTyCoOcc, mkEqPredCoOcc, mkClassOpAuxOcc,
532 mkCon2TagOcc, mkTag2ConOcc, mkMaxTagOcc,
533 mkVectOcc, mkVectTyConOcc, mkVectDataConOcc, mkVectIsoOcc,
534 mkPDataTyConOcc, mkPDataDataConOcc, mkPReprTyConOcc, mkPADFunOcc
535 :: OccName -> OccName
537 -- These derived variables have a prefix that no Haskell value could have
538 mkDataConWrapperOcc = mk_simple_deriv varName "$W"
539 mkWorkerOcc = mk_simple_deriv varName "$w"
540 mkDefaultMethodOcc = mk_simple_deriv varName "$dm"
541 mkClassOpAuxOcc = mk_simple_deriv varName "$c"
542 mkDerivedTyConOcc = mk_simple_deriv tcName ":" -- The : prefix makes sure it classifies
543 mkClassTyConOcc = mk_simple_deriv tcName "T:" -- as a tycon/datacon
544 mkClassDataConOcc = mk_simple_deriv dataName "D:" -- We go straight to the "real" data con
545 -- for datacons from classes
546 mkDictOcc = mk_simple_deriv varName "$d"
547 mkIPOcc = mk_simple_deriv varName "$i"
548 mkSpecOcc = mk_simple_deriv varName "$s"
549 mkForeignExportOcc = mk_simple_deriv varName "$f"
550 mkNewTyCoOcc = mk_simple_deriv tcName "NTCo:" -- Coercion for newtypes
551 mkInstTyCoOcc = mk_simple_deriv tcName "TFCo:" -- Coercion for type functions
552 mkEqPredCoOcc = mk_simple_deriv tcName "$co"
554 -- used in derived instances
555 mkCon2TagOcc = mk_simple_deriv varName "$con2tag_"
556 mkTag2ConOcc = mk_simple_deriv varName "$tag2con_"
557 mkMaxTagOcc = mk_simple_deriv varName "$maxtag_"
559 -- Generic derivable classes
560 mkGenOcc1 = mk_simple_deriv varName "$gfrom"
561 mkGenOcc2 = mk_simple_deriv varName "$gto"
563 -- data T = MkT ... deriving( Data ) needs defintions for
564 -- $tT :: Data.Generics.Basics.DataType
565 -- $cMkT :: Data.Generics.Basics.Constr
566 mkDataTOcc = mk_simple_deriv varName "$t"
567 mkDataCOcc = mk_simple_deriv varName "$c"
570 mkVectOcc = mk_simple_deriv varName "$v_"
571 mkVectTyConOcc = mk_simple_deriv tcName ":V_"
572 mkVectDataConOcc = mk_simple_deriv dataName ":VD_"
573 mkVectIsoOcc = mk_simple_deriv varName "$VI_"
574 mkPDataTyConOcc = mk_simple_deriv tcName ":VP_"
575 mkPDataDataConOcc = mk_simple_deriv dataName ":VPD_"
576 mkPReprTyConOcc = mk_simple_deriv tcName ":VR_"
577 mkPADFunOcc = mk_simple_deriv varName "$PA_"
579 mk_simple_deriv :: NameSpace -> String -> OccName -> OccName
580 mk_simple_deriv sp px occ = mk_deriv sp px (occNameString occ)
582 -- Data constructor workers are made by setting the name space
583 -- of the data constructor OccName (which should be a DataName)
585 mkDataConWorkerOcc datacon_occ = setOccNameSpace varName datacon_occ
589 mkSuperDictSelOcc :: Int -- ^ Index of superclass, e.g. 3
590 -> OccName -- ^ Class, e.g. @Ord@
591 -> OccName -- ^ Derived 'Occname', e.g. @$p3Ord@
592 mkSuperDictSelOcc index cls_occ
593 = mk_deriv varName "$p" (show index ++ occNameString cls_occ)
595 mkLocalOcc :: Unique -- ^ Unique to combine with the 'OccName'
596 -> OccName -- ^ Local name, e.g. @sat@
597 -> OccName -- ^ Nice unique version, e.g. @$L23sat@
599 = mk_deriv varName ("$L" ++ show uniq) (occNameString occ)
600 -- The Unique might print with characters
601 -- that need encoding (e.g. 'z'!)
605 -- | Derive a name for the representation type constructor of a
606 -- @data@\/@newtype@ instance.
607 mkInstTyTcOcc :: String -- ^ Family name, e.g. @Map@
608 -> OccSet -- ^ avoid these Occs
609 -> OccName -- ^ @R:Map@
610 mkInstTyTcOcc str set =
611 chooseUniqueOcc tcName ('R' : ':' : str) set
615 mkDFunOcc :: String -- ^ Typically the class and type glommed together e.g. @OrdMaybe@.
616 -- Only used in debug mode, for extra clarity
617 -> Bool -- ^ Is this a hs-boot instance DFun?
618 -> OccSet -- ^ avoid these Occs
619 -> OccName -- ^ E.g. @$f3OrdMaybe@
621 -- In hs-boot files we make dict funs like $fx7ClsTy, which get bound to the real
622 -- thing when we compile the mother module. Reason: we don't know exactly
623 -- what the mother module will call it.
625 mkDFunOcc info_str is_boot set
626 = chooseUniqueOcc VarName (prefix ++ info_str) set
628 prefix | is_boot = "$fx"
632 Sometimes we need to pick an OccName that has not already been used,
633 given a set of in-use OccNames.
636 chooseUniqueOcc :: NameSpace -> String -> OccSet -> OccName
637 chooseUniqueOcc ns str set = loop (mkOccName ns str) (0::Int)
640 | occ `elemOccSet` set = loop (mkOccName ns (str ++ show n)) (n+1)
644 We used to add a '$m' to indicate a method, but that gives rise to bad
645 error messages from the type checker when we print the function name or pattern
646 of an instance-decl binding. Why? Because the binding is zapped
647 to use the method name in place of the selector name.
648 (See TcClassDcl.tcMethodBind)
650 The way it is now, -ddump-xx output may look confusing, but
651 you can always say -dppr-debug to get the uniques.
653 However, we *do* have to zap the first character to be lower case,
654 because overloaded constructors (blarg) generate methods too.
655 And convert to VarName space
657 e.g. a call to constructor MkFoo where
658 data (Ord a) => Foo a = MkFoo a
660 If this is necessary, we do it by prefixing '$m'. These
661 guys never show up in error messages. What a hack.
664 mkMethodOcc :: OccName -> OccName
665 mkMethodOcc occ@(OccName VarName _) = occ
666 mkMethodOcc occ = mk_simple_deriv varName "$m" occ
670 %************************************************************************
672 \subsection{Tidying them up}
674 %************************************************************************
676 Before we print chunks of code we like to rename it so that
677 we don't have to print lots of silly uniques in it. But we mustn't
678 accidentally introduce name clashes! So the idea is that we leave the
679 OccName alone unless it accidentally clashes with one that is already
680 in scope; if so, we tack on '1' at the end and try again, then '2', and
681 so on till we find a unique one.
683 There's a wrinkle for operators. Consider '>>='. We can't use '>>=1'
684 because that isn't a single lexeme. So we encode it to 'lle' and *then*
685 tack on the '1', if necessary.
688 type TidyOccEnv = OccEnv Int -- The in-scope OccNames
689 -- Range gives a plausible starting point for new guesses
691 emptyTidyOccEnv :: TidyOccEnv
692 emptyTidyOccEnv = emptyOccEnv
694 initTidyOccEnv :: [OccName] -> TidyOccEnv -- Initialise with names to avoid!
695 initTidyOccEnv = foldl (\env occ -> extendOccEnv env occ 1) emptyTidyOccEnv
697 tidyOccName :: TidyOccEnv -> OccName -> (TidyOccEnv, OccName)
699 tidyOccName in_scope occ@(OccName occ_sp fs)
700 = case lookupOccEnv in_scope occ of
701 Nothing -> -- Not already used: make it used
702 (extendOccEnv in_scope occ 1, occ)
704 Just n -> -- Already used: make a new guess,
705 -- change the guess base, and try again
706 tidyOccName (extendOccEnv in_scope occ (n+1))
707 (mkOccName occ_sp (unpackFS fs ++ show n))
710 %************************************************************************
712 Stuff for dealing with tuples
714 %************************************************************************
717 mkTupleOcc :: NameSpace -> Boxity -> Arity -> OccName
718 mkTupleOcc ns bx ar = OccName ns (mkFastString str)
720 -- no need to cache these, the caching is done in the caller
721 -- (TysWiredIn.mk_tuple)
723 Boxed -> '(' : commas ++ ")"
724 Unboxed -> '(' : '#' : commas ++ "#)"
726 commas = take (ar-1) (repeat ',')
728 isTupleOcc_maybe :: OccName -> Maybe (NameSpace, Boxity, Arity)
729 -- Tuples are special, because there are so many of them!
730 isTupleOcc_maybe (OccName ns fs)
731 = case unpackFS fs of
732 '(':'#':',':rest -> Just (ns, Unboxed, 2 + count_commas rest)
733 '(':',':rest -> Just (ns, Boxed, 2 + count_commas rest)
736 count_commas (',':rest) = 1 + count_commas rest
740 %************************************************************************
742 \subsection{Lexical categories}
744 %************************************************************************
746 These functions test strings to see if they fit the lexical categories
747 defined in the Haskell report.
750 isLexCon, isLexVar, isLexId, isLexSym :: FastString -> Bool
751 isLexConId, isLexConSym, isLexVarId, isLexVarSym :: FastString -> Bool
753 isLexCon cs = isLexConId cs || isLexConSym cs
754 isLexVar cs = isLexVarId cs || isLexVarSym cs
756 isLexId cs = isLexConId cs || isLexVarId cs
757 isLexSym cs = isLexConSym cs || isLexVarSym cs
761 isLexConId cs -- Prefix type or data constructors
762 | nullFS cs = False -- e.g. "Foo", "[]", "(,)"
763 | cs == (fsLit "[]") = True
764 | otherwise = startsConId (headFS cs)
766 isLexVarId cs -- Ordinary prefix identifiers
767 | nullFS cs = False -- e.g. "x", "_x"
768 | otherwise = startsVarId (headFS cs)
770 isLexConSym cs -- Infix type or data constructors
771 | nullFS cs = False -- e.g. ":-:", ":", "->"
772 | cs == (fsLit "->") = True
773 | otherwise = startsConSym (headFS cs)
775 isLexVarSym cs -- Infix identifiers
776 | nullFS cs = False -- e.g. "+"
777 | otherwise = startsVarSym (headFS cs)
780 startsVarSym, startsVarId, startsConSym, startsConId :: Char -> Bool
781 startsVarSym c = isSymbolASCII c || (ord c > 0x7f && isSymbol c) -- Infix Ids
782 startsConSym c = c == ':' -- Infix data constructors
783 startsVarId c = isLower c || c == '_' -- Ordinary Ids
784 startsConId c = isUpper c || c == '(' -- Ordinary type constructors and data constructors
786 isSymbolASCII :: Char -> Bool
787 isSymbolASCII c = c `elem` "!#$%&*+./<=>?@\\^|~-"
790 %************************************************************************
793 Here rather than BinIface because OccName is abstract
795 %************************************************************************
798 instance Binary NameSpace where
801 put_ bh DataName = do
805 put_ bh TcClsName = do
810 0 -> do return VarName
811 1 -> do return DataName
812 2 -> do return TvName
813 _ -> do return TcClsName
815 instance Binary OccName where
816 put_ bh (OccName aa ab) = do
822 return (OccName aa ab)